The present invention relates to a pressure cylinder apparatus and to a hydraulic press incorporating the same.
As is well known, a hydraulic cylinder apparatus has a cylinder and a ram or piston (referred to as "slidable member", hereinunder) received by the cylinder, the slidable member being slidable outwardly and inwardly of the cylinder by fluid pressure applied to the slidable member in the cylinder, so that a force is applied to a member or a machine part fixed to the slidable member thereby to perform a desired work. In the operation of the pressure cylinder apparatus, therefore, the supply and discharge of the fluid to and from the cylinder is essential. As a matter of fact, the pressurizing force of the fluid introduced into the cylinder and acting on the piston has a certain directivity on the sliding movement of the slidable member. More specifically, it is well known that the slidable member is rotated more or less when it is forced out from the cylinder. This does not matter if the slidable member is allowed to rotate while moving ahead. However, in the case where the rotation of the slidable member during linear forward movement is strictly forbidden, it is necessary to employ a considerably complicated guide means for preventing the slidable member from rotating. The size of the guide means is increased and the construction of the same is complicated as the whole apparatus becomes larger in size and complicated in construction.